WO1993024215A1

WO1993024215A1 - Process and device for producing granulates from powdery material

Info

Publication number: WO1993024215A1
Application number: PCT/EP1993/001328
Authority: WO
Inventors: Werner Schleicher; Stefan Leiner; Detlef Bednarek; Bernhard Hassel; Philipp SPÄTH
Original assignee: Boehringer Ingelheim Vetmedica Gmbh
Priority date: 1992-05-30
Filing date: 1993-05-27
Publication date: 1993-12-09
Also published as: AU673675B2; CA2136009A1; FI945618A; KR950701837A; EP0642383A1; RU2131295C1; DK0642383T3; DE4217971C1; RU94046213A; DE59309436D1; CZ292794A3; EP0642383B1; NO944581L; NZ253083A; JPH07507230A; AU4318393A; ATE177343T1; ES2130270T3; FI945618A0; GR3030318T3

Abstract

A process is disclosed for constructively granulating a powdery material in a fluidized bed equipment. The granulating liquid containing a binder is sprayed downwards on the fluidized bed of material to be granulated in countercurrent to the fluidized bed-generating gas by means of two-component fan jet nozzles. With charge quantities on the order of about 1000 kg, very uniform and dust-free granulates can thus be obtained.

Description

Method and device for producing granules from powdery material

The invention relates to a process for the build-up granulation of a powdery material and / or the encapsulation of a granulate in a fluidized bed with a binder contained in a granulating liquid, in which the material in a fluidized bed apparatus through a gas stream blown from below through a sieve tray, at least in some areas of its bed fluidized and the granulating liquid is sprayed into fluidized zones of the material. The invention further relates to a device for performing such a method.

Medicinal products, feed additives and other products often occur at the end of their actual manufacturing process as a powder or powder mixture with a certain particle size distribution.

REPLACEMENT LEAF Even a product that is chemically or otherwise suitable for a particular application can sometimes not fully develop its effect under practical conditions or be restricted in its handling if it is not presented in a suitable external form. The solution to problems of insufficient chemical resistance or dangerous handling of a powdery material due to dust formation can in some cases be the granulation of the powdery material and the possible additional coating of the granulate particles with an otherwise non-interfering protective substance.

For a feed additive containing zinc bacitracin, EP-A-165 577 shows how granulation can significantly improve the chemical resistance of such feed additive in a feed mixture. According to EP-A-165 577, the use of a fluidized bed granulator is proposed as the preferred method for granulating, in which the powdery starting material is specified and, after generating a fluidized bed, by blowing a gas stream through a sieve tray on which the starting substance rests, a granulating liquid is sprayed in using spray nozzles the fluidized bed is sprayed in, which contains 1-10% by weight of a suitable binder in solution or suspension, which causes an increasing agglomeration of the powdery material to form a granulate and finally covers this with a protective layer.

While it is in the subject of EP-A-165 577 essentially on the improvement of the chemical resistance of a zinc bacitracin containing

REPLACEMENT LEAF When the feed additive arrived in a feed mixture, EP-A-302 462 describes an improved granulation process in general for

Feed additives in which a split-top dynamic filter granulating apparatus is used for granulating. Such an apparatus is described in DE-A-29 32 803, to which reference is also made in EP-A-302 462, and in a somewhat different embodiment in later EP-A-331 111. It is a fluidized bed apparatus, in which a rotor is arranged in the wind chamber under the sieve tray, which allows the fluidizing gas to be blown in only in certain radially extending zones which move slowly through the rotation of the rotor, so that only in certain circular sector-like sections create fluidized bed areas that slowly migrate through the material bed.

While the apparatus according to DE-A-29 32 803 only provides a single spray nozzle which is arranged centrally above the sieve bottom and which sprays the coating or granulating liquid into the fluidized bed from below, the apparatus according to EP-A-331 111 radial arms above the sieve bottom are provided with upwardly directed spray nozzles which rotate synchronously with the gap rotor, so that they migrate with the fluidized fluidized bed zones and spray the granulating liquid into them from below.

In EP-A-302 462 it is again shown using the example of a feed additive containing zinc bacitracin that the in the

Split-bed fluidized bed equipment not only produces granules that have an even better chemical resistance

REPLACEMENT LEAF has, but also a very narrow and uniform particle size distribution of the granules, which hardly contains oversize particles and is practically dust-free. In addition, the dust generated in an abrasion test hardly contains any of the active ingredient zinc bacitracin.

As can be seen from the exemplary embodiments of EP-A-302 462, batches of the order of 3 kg of starting material were processed there. Feed additives are required on a ton scale. In order to enable economical production, it is desirable to carry out granulations in batches of several hundred kilograms up to a ton.

The invention is based on the object of providing a process for the build-up granulation of powdery material and a corresponding device which, particularly on an industrial scale, lead to uniform and essentially dust-free granules, the properties of which correspond to the results from EP-A-302 462 corresponds.

It is known to the person skilled in the art that the fluidic behavior of substances strongly depends on the external conditions, including the apparatus used. In any case, this also applies to pelletizing processes with fluidized bed apparatus. The experiments were carried out with a fluidized bed apparatus with a diameter of about 2, the batches of powdery material being about 750 kg. However, it is assumed that the results obtained can also be transferred analogously to apparatuses of other sizes. The attempts

REPLACEMENT LEAF were also carried out in this case with a feed additive containing zinc bacitracin, the composition and other conditions of which can be found in EP-A-165 577 and EP-A-302 462, to which express reference is made. Even if the tests carried out primarily aimed at granulating a feed additive containing zinc bacitracin on an industrial scale with given properties, the present invention is not restricted to such feed additive, but is generally suitable for granulating powdered material, in the range of starting materials and granulating liquids as it results from EP-A-302 462, to which express reference is also made for this reason.

Also of special interest are cimaterol,

Sputolysin, bisolvon, virginiamycin, tylosin,

Spiramycin, nosiheptide, penicillins,

Chlorotetracyclines, oxytetracyclines, tetracyclines,

Erythromycine, furazolidone, nitrofuran,

Thrimethoprim, sulfonamides, dimetridazole,

Neomycin base and all pharmaceutically or food-approved vitamins - such as Vitamin A, A., A ,, B., B_, B., B-,

B._, C (ascorbic acid), ascorbyl palmitate and other pharmacologically acceptable derivatives of

Ascorbic acid, D, D. ,, D_, D. ,, D., E, H, K,

K1,, K2 ", P and Q - or active ingredients - such as

Avoparcin, Flavopholipol, Monensin, Monensin Sodium, Salinomycin, Carbadox, Nitrovin and Olaquindox.

The task is to improve a method of the type mentioned

REPLACEMENT LEAF solved according to the invention in that the granulating liquid is sprayed into the fluidized zones of the material by means of flat jet nozzles from above the fluidized bed, essentially in countercurrent to the gas stream forming the fluidized bed. A fluidized bed apparatus which is suitable for carrying out the method according to the invention is accordingly characterized in that the spray nozzles used are flat jet nozzles which are arranged in an upper region of the container which, when the device is operated as intended, lies above the fluidized bed which is being formed, and which their spray direction are directed essentially downwards against the fluidized bed.

It has been shown on an industrial scale in a larger apparatus that spraying the granulating liquid from below, i.e. from the sieve bottom up into the fluidized material zones is obviously not the optimal route. In particular in the case of a fluidized bed which is only formed in partial areas, such as by the gap-gyro process, the fluidizing gas appears to take the pelletizing liquid which is blown in in cocurrent upwards, so that it does not come into optimal contact with the material to be agglomerated. It has therefore proven to be more effective to spray the granulating liquid from above, quasi in countercurrent, to the fluidizing gas into the fluidized areas. The best effect was further achieved with flat jet nozzles, which are preferably aligned in a container with a circular cross-section so that the elongated surface covered by the jet extends with its long main axis essentially in the direction of a radius jet of the device.

REPLACEMENT LEAF Have proven to be the most effective nozzles

Two-component flat jet nozzles with an external mixture have been proven, in which the liquid to be atomized is atomized by an auxiliary gas stream after emerging from the nozzle and is brought into the desired jet shape. The reasons for the advantageous effect of these nozzles could not be clarified in detail, but presumably, despite the auxiliary pressure of the atomizing gas, a soft, well-distributed jet with droplet dynamics is generated, which in combination with the whirled up, powdery material produces a particularly uniform agglomeration effect.

It has also been found that when a suitable number of flat jet nozzles are distributed over the fluidized bed, it is generally no longer necessary to use the rotating gap gyro, i.e. to create limited fluidized bed areas which rotate slowly through the device. Good results were achieved almost equally with a sieve tray fully loaded with fluidizing gas. It is also not absolutely necessary to let the flat jet nozzles move over the fluidized bed, although this is a preferred embodiment of the method according to the invention. Whether this measure is necessary depends on the one hand on the number and distribution of the nozzles and on the other hand on the dynamics of the fluidized bed. It was found that even with flat jet nozzles, which only cover about 12% of the surface of the fluidized bed, a uniform granulate can be achieved. Here the duration of the spraying and the circulation effect in the fluidized bed are probably included in the process result.

REPLACEMENT LEAF The choice of the number of nozzles is not free in that a limited amount of granulating liquid is to be sprayed into a material batch, the spraying having to extend over a certain period of time in order to achieve slow agglomeration and granulation, the fluidizing gas also in must be able to remove the solvent or suspending agent of the granulating liquid. On the other hand, since the nozzles used have to be subjected to a certain throughput, it is not possible to spray the entire surface of the fluidized bed. Preferably, according to the invention, only about 10-25% of the surface of the fluidized bed is covered by the spray jets at any time. This may make it necessary to move or rotate the nozzles over the fluidized bed for better spray distribution.

In general, 2.5-30% by weight, preferably 5-20% by weight, based on the final granules, of binder will be introduced into the product, the granulating liquid containing 1-30%, preferably 2-10% Is, particularly preferably 5-7% solution or suspension of the binder.

In a special process variant, it is conceivable to first spray the pure active substance onto the carrier material and to coat it with the coating material in a second process step. In this process variant, the proportion by weight of the active ingredient is between 0.01 to 30% by weight, based on the end granules, depending on the pharmacological activity of the active ingredient. The active ingredient can be in the form of a solution - for example

REPLACEMENT LEAF a 0.01 to 30% by weight solution - or, in the case of less readily soluble active ingredients, also sprayed on in the form of a suspension. When setting the concentration of the active ingredient-containing solution, the type of solvent and the dissolving behavior of the active ingredient in the solvent must of course also be taken into account.

This is of particular interest

Process variant for highly active substances, e.g. Clenbuterol or sputolysin. For example, inorganic carriers such as e.g. Calcium carbonate or dicalcium phosphate, as organic carrier e.g. Sugars such as lactose, lactose maize starch or sucrose but also sorbitol can be considered.

In the experiments carried out with the feed additive, about 5% methyl cellulose, based on the end granules, was used, a 5% aqueous solution of the methyl cellulose being specified as the grilling liquid. Other coating materials are conceivable, as are disclosed for example in EP-A 165 577 and 302 462 - to which reference is made.

In addition to methyl cellulose, hydroxypropyl cellulose,

Hydroxypropylmethylcellulose, polyethylene glycol and water soluble starch.

With 5% binder input and 5% solution, the total amount of granulation liquid in liters corresponds approximately to the weight in kg of the specified powdery material. This amount of liquid was used to achieve a good result

REPLACEMENT LEAF preferably sprayed into the fluidized bed over a period of 3-4 hours. The amount of liquid per unit of time need not necessarily be kept constant over the entire spraying time. Rather, a little more can be sprayed at the beginning of the process and a little less towards the end. With an amount of about 1 liter of granulating liquid per kg of powdered material and a spraying time of just under 3.5 hours, the average spraying time is only about 5 ml / kg of starting material and minute. It already follows from this that the spray density at the top of the fluidized bed cannot be kept very high.

Spraying Systems offers, for example, two-component flat jet nozzles which are suitable for the process according to the invention. In the experiments, a nozzle from this company with the type designation SUE 45 has proven to be suitable and has a spray angle of 45 °. According to the supplier's specification, this nozzle has a liquid throughput of 4.7 1 / min for operation with water at a liquid pressure of 1.5 bar and an air pressure of approximately 6.0 bar. With a liquid inlet pressure of 0.7 bar and an air pressure of 5-6 bar, the water throughput drops to 3.2 1 / min. In the case of highly viscous liquids, such as the granulating liquids in question here, the liquid throughput of the nozzles is considerably lower. The viscosity of the liquid can also be influenced by its temperature. It has been found that the nozzles with the granulating liquid work satisfactorily if the viscosity of the liquid is chosen such that the nozzles achieve 0.1-0.3 times the throughput, preferably 0.12-0.18 times the throughput of

REPLACEMENT LEAF Have nominal flow rate with water. The nozzles are preferably operated with a pressure of the atomizing gas between 2 and 6 bar. The liquid pressure is determined by the desired throughput of the nozzle. It can vary between 0.7 and 3 bar, preferably it is between 1.2 and 1.8 bar. With a 5%

Methyl cellulose solution with a temperature of 30 ° C is the throughput with the nozzle type mentioned about 0.6-1.4 1 / min.

Depending on the distance of such a nozzle from the surface to be sprayed, here the theoretical one

Surface of the fluidized bed, the nozzle sprays one

2 area of 150-750 cm, with a spray area

2 between 500 and 700 cm is preferred, for which the average distance of the nozzle from the surface to be sprayed is approximately 70 cm. The preferred spray density, based on the area actually sprayed, is preferably between 5 and

The number of nozzles required results from the spraying power of the individual nozzles and the amount of granulating liquid to be sprayed per unit of time, the number of nozzles required being selected, in particular the height arrangement of which gives the preferred area to be sprayed. In the case of an apparatus with a circular cross section, the nozzles are preferably arranged in such a way that their spray fields show a radial course and are evenly distributed over the circumference in terms of their spacing. If the length of the spray field of a nozzle is approximately sufficient to detect a container radius, a nozzle ring is preferably selected, the nozzles being approximately in the

REPLACEMENT LEAF half radius distance from the center are arranged. With a container with a diameter of 2 m, for example, good results could be achieved with six nozzles arranged in this way and distributed over the circumference. With a larger container diameter, a higher number of nozzles may be required, whereby the nozzles, if they do not cover almost the length of a container radius, should be arranged alternately at different distances from the center of the container in such a way that the spray distribution over the fluidized bed is as uniform as possible becomes. Based on the whole

Fluidized bed area has a spray density between

2

1 and 3 1 / m .min, preferably between 1.2 and

2

1.5 1 / m .min proved to be suitable.

Gas quantities in the range of 10-60 m 3 / mm .m 2 sieve plate have proven to be suitable for producing the fluidized bed. The method according to the invention therefore proves to be particularly economical in this respect. In contrast to some known ones

The process has no particular influence on the process according to the invention whether the current of the

Fluidizing gas through the sieve tray through a

Overpressure is generated under the sieve plate or a negative pressure above the sieve plate. To generate the gas flow, either a pressure-generating fan on the gas space below the

Sieve bottom or a suction fan on the product space above the fluidized bed.

When processing the one chosen in the tests

Feed additive could successfully with a specific sieve floor load of 200-300 kg of

2 powdery starting material per m

Sieve bottom surface to be worked. As fluidizing gas

REPLACEMENT LEAF In the special case, nitrogen was used, the entry temperature of which into the granulating device was in a temperature range between 90 and 110 ° C., preferably 100 ° C. The powdery material was heated to a temperature above 70 ° C, preferably 80 ° C, before starting spraying. The basic structure of an embodiment of a fluidized bed apparatus according to the invention is explained below with reference to the accompanying drawings. In it represent:

Fig. 1 shows a schematic vertical section through the essential parts of the device and

Fig. 2 is a schematic horizontal section through the device, in which the distribution of the spray nozzles can be seen.

The fluidized bed granulator shown in Fig. 1 in schematic cross section has a product container 2 for the pulverulent material to be granulated, which is closed at its lower end by a fine sieve plate 4, the fineness of which is selected so that the pulverulent material to be carried by it is not to a significant extent can pass through the sieve bottom. An upper part 6 of the granulator is arranged above the product container 2 and in its continuation upwards. This upper part has a cylindrical outer jacket 8, which is closed at its top by an upper wall 10. A wind chamber 12, which is provided with gas inlet openings 14 and which is connected to a blower (not shown), is arranged below the product container 2 or from the sieve bottom 4 thereof

REPLACEMENT LEAF stand. In the upper part 6 of the device there is a gas outlet opening 16 through which the fluidizing gas can leave the device again. The dashed line 18 in the upper part of the device schematically indicates a dust filter which is to hold back dust particles from the powdery material carried by the fluidizing gas and, depending on the design, either to return to the product container from above or to collect it for other treatment.

In the lower part of the central axis of the device there is a rotatable shaft 22 driven by a motor 20, which passes through the sieve bottom from below and is provided with spray arms 24 above the sieve bottom, each of which is provided with a two-component flat jet nozzle 26 at its end are. From Fig. 2 it can be seen that the shaft 22 is equipped with six spray arms distributed at equal angular intervals over the circumference of the device, which together carry six spray nozzles, which are in their position approximately at half the radius distance from the shaft 22 to the outer wall of the device are located. The shaft 22 and the spray arms 24 are hollow in order to be able to supply spray liquid to the nozzles 26 with feed means (not shown).

In the drawing, the product container 2 is not provided with a loading opening for the powdery material, but rather, as a whole, including the sieve bottom 4 for loading and unloading, can be led out laterally from the fluidized bed apparatus, which is indicated by the interruption 28 in the outer wall of the device . The device is intended for batch operation.

REPLACEMENT LEAF In the version of the fluidized bed apparatus used for experiments, the diameter of the product container and the upper part was approx. 2 m, which was at

Subtracting the cross section of the shaft 22 above the sieve bottom resulted in a sieve bottom area of approximately 3.1 m 2. When spray nozzles were

Two-component flat spray nozzles from Spraying

Systems, of the type SUE 45. The

Nozzles were arranged about 145 cm above the sieve plate 4. This resulted in a generated

Fluid bed height above the sieve bottom of about 75 cm, a nozzle distance from the fluid bed of about

70 cm. The nozzles were at a gas pressure of about

4 bar operated. At a liquid pressure of approximately 1.5 bar, such a nozzle has one

Water flow of about 4.7 1 / min. When spraying a 5% aqueous methyl cellulose solution, the throughput per nozzle is depending on

Liquid pressure about 0.6-1.4 1 / min.

The drive for shaft 22 was designed to be adjustable for speeds between 0.2 and 10 rpm.

A powdered feed additive containing zinc bacitracin was granulated with the fluid bed apparatus described above. A typical embodiment is shown below:

Embodiment

In the product container of the fluidized bed apparatus described above, 712.5 kg of a powdered feed additive containing zinc bacitracin were specified. The powder had

REPLACEMENTB a grain size distribution of 1-40 .mu.m, the majority of the grain size distribution being in a range of 10-15 .um. In addition to 5-30% by weight of zinc bacitracin, such a powder also contains fermentation residues from the manufacturing process and calcium carbonate.

Nitrogen was used as the fluidizing gas. At the beginning of the process, the powdery starting material was heated to 80 ° C. for about 20 minutes using nitrogen gas at 95 ° C.

For the spraying of the granulating liquid which then commenced, six flat jet nozzles with their jets directed downward onto the fluidized bed were used, which rotated through the device at a speed of 6 rpm. A total of 750 liters of a 5% strength methyl cellulose solution with a temperature of 30 ° C. were sprayed in.

To produce the fluidized bed, nitrogen gas of approximately 100 ° C. was introduced in increasing amounts into the

Blown in apparatus, initially with a

3 rate of 40 m / mm and towards the end at a rate of 187 m 3 / mm. . The spray rate of the

Granulating liquid was initially 4 1 / min and was added after a sprayed amount of

20 1 increased by 1 1 / min to a total of 8 1 / min.

As the spray rate increased, the amount of Fluidi .si.ergas increased by 10 m3 / mm

3rd ... .. increased to 90 m / mm. After spraying in

The spray rate was reduced to 4 l / min and kept constant at 120 l of granulating liquid. The total spraying time was about 3 hours.

REPLACEMENT BL After the spraying and washing of the nozzles with a certain amount of water had ended, the granules produced were dried. The product temperature and the exhaust air humidity of the dry air were checked.

The particle size distribution of the granules was very uniform, the granulate fraction of particles between 180 and 710 µm was over 80%, which corresponded to the specified specification. In the range between 125 and 1000 .mu.m lay over 98% of the granulate. The fines content of particles with less than 45 .mu.m was 0.01% and was also in the specified specification.

It was therefore possible to produce a fully satisfactory granulate by the process according to the invention and with the fluidized bed apparatus according to the invention.

Analogous to the example described, tests were also carried out on an industrial scale with calcium carbonate and lactose as carriers and further tests with soluble starch as coating material.

REPLACEMENT LEAF

Claims

1. A process for the build-up granulation of a powdery material and / or the encapsulation of a granulate in a fluidized bed with a binder contained in a granulating liquid, in which the powdered material is fluidized in a fluidized bed apparatus by a gas stream introduced from below through a sieve tray, at least in some areas of its bed and the granulating liquid is sprayed into fluidized zones of the material, characterized in that the granulating liquid is sprayed into fluidized zones of the material from above the fluidized bed by means of a flat jet nozzle (s), essentially in countercurrent to the gas stream forming the fluidized bed.

2. The method according to claim 1, characterized in that

Two-substance overpressure flat jet nozzles are used for external mixing, which are operated with a pressure of the atomizing gas of 2 to 6 bar.

3. The method according to claim 1 or 2, characterized in that several flat jet nozzles are used, which are distributed as uniformly as possible over the surface of the fluidized bed.

4. The method according to at least one of claims 1 to 3, characterized in that the material bed is fluidized only in partial areas and these partial areas and in

REPLACEMENT LEAF According to them, the flat jet nozzles are allowed to move through the fluidized bed apparatus.

Method according to at least one of claims 1 to 3, characterized in that essentially the entire bed of material is fluidized in the fluidized bed and the flat jet nozzles are allowed to move over the fluidized bed.

Method according to at least one of claims 1-5 for the processing of a feed additive containing zinc bacitracin, characterized in that in the fluidized bed apparatus with a specific

Filling of 200-300 kg of the starting material per m 2 of sieve bottom area is worked, and a 4 to 6% by weight aqueous solution of methyl cellulose is used as the granulating liquid.

Fluidized bed apparatus, with a container (2, 6), a sieve tray (4) arranged in the container (2) for carrying powdery material, one arranged below the sieve tray (4)

Device (12, 14) for initiating

Fluidizing gas through the sieve tray into the

Material and at least one spray nozzle (26) arranged above the sieve bottom (4) for spraying

Granulating liquid, and means for supplying the granulating liquid to the at least one

Spray nozzle (26),

REPLACEMENT LEAF characterized in that the at least one spray nozzle (26) is a flat jet nozzle which is arranged in an upper region of the container (6) which, when the device is operated as intended, lies above the fluidized bed which is being formed, and which, with its spray direction, is essentially downward is directed against the fluidized bed.

8. fluidized bed apparatus according to claim 7, characterized in that the at least one spray nozzle (26) one

Two-component overpressure flat jet nozzle with external mixture is.

9. fluidized bed apparatus according to claim 8, characterized in that the at least one flat jet nozzle (26) is designed for a pressure of the atomizing gas of 2 to 7 bar and for a pressure of the granulating liquid to be atomized from 0.2 to 3.0 bar.

10. fluidized bed apparatus according to claim 8 or 9, characterized in that the at least one flat jet nozzle (26) is designed for a liquid throughput, based on water, from 1.5 to 5.0 1 / min.

11. fluidized bed apparatus according to at least one of claims 7 to 10 with a container (2, 6) with a substantially circular cross-section, characterized in that the at least one flat jet nozzle (26) with its spray field in

REPLACEMENT LEAF is oriented essentially radial direction, wherein the spray field, with respect to the vertical central axis (22) of the container, extends only on one side thereof along a radial jet, and the spray nozzle (26) is rotatable about the central axis of the container.

12. Fluidized bed apparatus according to claim 11, characterized in that a plurality of flat jet nozzles (26), preferably 6-12 flat jet nozzles, are arranged distributed uniformly over the circumference of the container (2, 6).

13. fluidized bed apparatus according to claim 11 or 12, characterized in that the flat jet nozzles (26) by means of arms (24) are attached to a central rotary shaft (22) and optionally the supply of the granulating liquid to the flat jet nozzles (26) through the hollow rotary shaft ( 22) and the arms (24) is provided.

14. fluidized bed apparatus according to at least one of claims 11 to 13, characterized in that under the sieve bottom a rotatable plate with substantially radial

Air passage slots is arranged which are rotatable in accordance with the flat jet nozzles.

15. Fluidized bed apparatus according to at least one of claims 7 to 10 with a container with a substantially circular cross section, characterized in that a plurality of flat jet nozzles

REPLACEMENT LEAF their spray field are distributed in a substantially radial orientation at approximately the same distance over the circumference of the container.

16. Fluidized bed apparatus according to claim 15, characterized in that 6 to 12 flat jet nozzles are provided.

17. Fluidized bed apparatus according to at least one of claims 12 to 16, characterized in that the area of the fluidized bed detected by the flat jet nozzles at any time is approximately 10 to 25% of the total area of the fluidized bed.

18. fluidized bed apparatus according to at least one of claims 12 to 17, characterized in that the surface of the fluidized bed detected by a flat jet nozzle 150 to 750 cm 2, preferably

600-700 cm 2.

19. Use of a fluidized bed apparatus according to one of claims 7-18 for the build-up granulation of a powdery material and / or the coating of a granulate with a binder contained in a granulation liquid.

20. Use of a fluidized bed apparatus according to one of claims 7-18 for constructive granulation of a feed additive containing powdered zinc bacitracin.

REPLACEMENT LEAF